Thanks. Now is this answer the area, or probability? He needs to find the probability.

Yes, the probability is the shaded region divided by the circle area.

The circle contains the total area.
The shaded region is the "difference" between the circle area and the square area.
Hence the square area is subtracted from the circle area to obtain the numerator of the probability fraction.

Well that sucks. I will tell him to solve the problem the same way you guys solved the other problem. Thanks for your help!!!

The reason that 5/6 is wrong is that the six triangles are not all the same size. The two triangles in the central diamond are larger than the four triangles around the outside, in fact their area is twice as large.